Detecting passing of unintended objects through throat of under-sink disposal

Abstract

An under-sink disposal unit includes a motor, a disposal chamber, and a disposal throat. The disposal throat extends from the disposal chamber to an opening in a top of the disposal unit and defines a passageway through which objects pass into the disposal chamber for grinding. The disposal unit further includes a coil assembly including an arrangement of coils. The arrangement of coils is used to detect the passing of a metallic object in the passageway through the disposal throat. Furthermore, the arrangement of coils includes at least one coil having a loop that is oriented with respect to an axis of the passageway through the disposal throat such that objects passing through the disposal throat into the disposal chamber pass by and proximate to, but do not pass through, such loop. Preferably DC injection braking is used to stop the motor upon detection of a metallic object.

What is claimed is: 
     
       1. An under-sink disposal unit, comprising a passageway through which objects pass into a disposal chamber for grinding, and a coil assembly and associated electronics configured to detect the passing of a metallic object through the passageway, wherein the arrangement of coils comprises,
 (a) a first coil comprising a loop that is oriented with respect to an axis of the passageway such that objects passing through the passageway pass by and proximate to, but do not pass through, the loop of the first coil, 
 (b) a second coil comprising a loop that is oriented with respect to the axis such that objects passing through the passageway pass by and proximate to, but do not pass through, the loop of the second coil, and 
 (c) a third coil comprising a loop that is oriented with respect to the axis such that objects passing through the passageway pass through the loop of the third coil. 
 
     
     
       2. The under-sink disposal unit of  claim 1 , wherein at least one loop of the arrangement of coils comprises multiple windings of an electrically conductive wire. 
     
     
       3. The under-sink disposal unit of  claim 1 , further comprising a collar extending around the passageway to which collar the arrangement of coils are secured. 
     
     
       4. The under-sink disposal unit of  claim 3 , wherein the collar completely encompasses the passageway. 
     
     
       5. The under-sink disposal unit of  claim 3 , wherein the collar is generally commensurate in extent with the passageway. 
     
     
       6. The under-sink disposal unit of  claim 3 , wherein the collar extends between a locking ring, whereat the disposal unit is configured for attachment to an underneath of a sink, and a top of the disposal chamber. 
     
     
       7. The under-sink disposal unit of  claim 3 , wherein the collar extends around the passageway along an entire extent of the passageway between the disposal chamber and a top of the disposal unit. 
     
     
       8. The under-sink disposal unit of  claim 1 , wherein the arrangement of coils are contained within a housing of the under-sink disposal unit. 
     
     
       9. The under-sink disposal unit of  claim 1 , wherein the third coil further comprises an additional loop that is oriented with respect to the axis such that objects passing through the passageway pass through the additional loop of the third coil. 
     
     
       10. The under-sink disposal unit of  claim 9 , wherein the loops of the third coil are electrically connected in series. 
     
     
       11. The under-sink disposal unit of  claim 9 , wherein each loop of the third coil comprises multiple windings of an electrically conductive wire. 
     
     
       12. The under-sink disposal unit of  claim 9 , wherein the third coil is a transmit coil, and wherein the first and second coils are receiver coils. 
     
     
       13. The under-sink disposal unit of  claim 9 , wherein the first and second coils are not electrically connected in series or parallel. 
     
     
       14. The under-sink disposal unit of  claim 9 , wherein each coil is respectively connected to a controller comprising circuitry used to detect, via the coil assembly, the passing of a metallic object in the passageway through the disposal throat. 
     
     
       15. The under-sink disposal unit of  claim 14 , wherein the controller is configured to cut power to a motor of the under-sink disposal unit upon the detecting of the passing of a metallic object through the passageway. 
     
     
       16. The under-sink disposal unit of  claim 14 , wherein the motor is an alternating current motor, wherein the under-sink disposal unit further comprises an AC to DC converter, and wherein the controller is configured to cause current to the motor to switch from alternating current to direct current from the AC to DC converter upon the detecting of the passing of a metallic object through the passageway, whereby DC injection braking is performed. 
     
     
       17. An under-sink disposal installation, comprising:
 (a) a sink; and 
 (b) an under-sink disposal unit comprising,
 (i) a disposal chamber, 
 (ii) a disposal throat that defines a passageway through which objects pass from the sink to the disposal chamber, and 
 (iii) a coil assembly comprising an arrangement of coils and associated electronics used to detect the passing of a metallic object through the passageway of the disposal throat, the arrangement of coils comprising,
 (A) a first coil comprising a loop that is oriented with respect to an axis of the passageway such that objects passing through the passageway pass by and proximate to, but do not pass through, the loop of the first coil, 
 B) a second coil comprising a loop that is oriented with respect to the axis such that objects passing through the passageway pass by and proximate to, but do not pass through, the loop of the second coil, and 
 (C) a third coil comprising a loop that is oriented with respect to the axis such that objects passing through the passageway pass through the loop of the third coil. 
 
 
 
     
     
       18. The under-sink disposal installation of  claim 17 , wherein the arrangement of coils is contained within a housing of the under-sink disposal unit.